The present invention relates to valves, and particularly to the quarter-turn valve which is manually turnable one-quarter turn to open or close the valve.
One known type of quarter-turn valve comprises a housing formed with a cylindrical socket, and a cylindrical plug receivable within the socket. The housing includes an inlet nipple at one side of the socket, and an outlet nipple at the diametrically opposite side of the socket. The cylindrical plug receivable within the socket has a bore extending diametrically through the plug for establishing communication between the inlet and outlet nipples in the open position of the plug, but terminating the communication when the plug is turned one-quarter turn from the open position. The plug is further formed with a finger-piece projecting from the housing for manually rotating the plug to its open, closed or an intermediate position.
In one known valve of this type, the plug is open at its bottom, and is retained in the socket by a screw-and-slot connection, which connection also limits the open and closed positions of the plug. In such an arrangement, the fluid pressure urges the plug outwardly of the socket, against its screw-and-slot connection. This imposes a retarding force against manually turning the plug to its open or closed position. Moreover, there is great danger of accidental ejection of the plug from the socket in the event of an excessively high pressure.
In addition, in the above-described known quarter-turn valve, the sealing rings, which are disposed within annular recesses formed in the plug, tend to unseat from the plug as they pass through the nipple openings when the plug is rotated within the socket. Further, in this type valve, it is difficult to manually remove the plug from the socket for repair or maintenance purposes.
An object of the present invention is to provide a quarter-turn valve having advantages in the above respects.